The field of this invention includes devices for warming beverages prior to consumption and in particular it includes portable self-contained devices for this purpose.
Self-warming containers for beverages have been known a comparatively long time. Early devices used incendiary or pyrotechnic materials as a heat source, and thus were only suitable for field use by troops or others whose background or training enabled them to safely handle such units, and were not suited for general consumer use or use in confined spaces such as motor vehicles or workplace lunchrooms.
A comparative improvement was achieved by the use of self-contained exothermic reactions in the liquid phase, reaching lower temperatures and generating a lesser amount of gas byproducts, or no gas at all, rendering them more suitable for widespread consumer use. These devices typically employed a hygroscopic salt or mineral, such as xe2x80x9cquicklimexe2x80x9d or CaO (calcium oxide) with a vigorous hydration reaction with water, which must have suggested early on the idea of employing quicklime as a chemical food heater.
Nonetheless, despite numerous entries in the field, the widespread prevalence of situations where a need for a hot beverage is perceived but in which no satisfactory method exists to fulfill that need, by inspection of the marketplace, demonstrate no existing product has successfully met the combined requirements of low retail cost, simplicity of use and manufacture, adequate safety, convenience and effectiveness in warming beverages to their ideal temperature. Safety, low cost and simplicity of use are likely to be important factors affecting consumers"" decision to purchase a container assembly that warms a cup of coffee or other beverage. Accordingly, there remains an unsatisfied need for improved portable warming devices that perform with adequate safety, simplicity and cost-effectiveness and can provide hot beverages to individuals on the move or away from cooking facilities.
In heating beverages by an exothermic reaction occurring in a closed container, a means must be provided of initiating that reaction. Typically this is achieved by providing two reactants in physically separate compartments with a partition between the compartments which is breached by some mechanical means in order to activate the device. This method in general creates some opposing design objectives. On the one hand the method of breaching the partition should be mechanically simple and reliable. On the other hand it is undesirable to allow a significantly exothermic reaction to proceed by means of a simple trigger which may be inadvertently activated since that would result in danger from unexpected heat and would cause immediate heat dissipation rendering the container assembly useless. While the possibility of inadvertent activation may be prevented by including in the device multiple safety interlocks, e.g., elements of the device which must be removed or manipulated prior to initiating the exothermic reaction, the inclusion of such interlocks contravenes the goal of simplicity of manufacture, and hence low cost, and the goal of simplicity of operation and hence convenience and appeal.
U.S. Pat. No. 3,970,068 to Sato, for example, teaches an internal plunger which is actuated by pushing in a dimple or raised area on a bottom of a self heating can, the plunger thereby piercing an internal hemispherical partition between compartments containing solids and liquid. To prevent unintended actuation, Sato also teaches a second or false bottom on the can, which must be removed to expose the dimple prior to activating the can. This second or false bottom complicates the design, yet is rendered necessary to protect the dimple and underlying plunger, lest they be inadvertently depressed or activated by a child, and cause rapid and unexpected high temperatures.
In U.S. Pat. No. 4,528,218 to Maoine the reaction follows an immediate and complete mixing of the two reactants upon actuation of the device. Thus unintended depression of the activating area or unmonitored operation by a child would immediately generate high temperatures.
U.S. Pat. Nos. 4,762,113 and 4,895,135 to Hamasaki disclose devices incorporating at least one primary water bag partially surrounding an inner beverage container and normally concealed and protected by an outer shell, on removal of a section of which shell, a protruding corner of the bag is exposed, and the bag may be ruptured by a pull on this corner of the bag. This method requires significant manual dexterity to activate; a thin corner of the bag must be grasped with possibly wet or cold fingers and pulled with sufficient force to rupture the bag. This method may also be perceived as less than a fully aesthetic solution by some consumers, since a corner of the water bag continues to protrude from between inner and outer shells or containers after activation.
U.S. Pat. No. 4,809,673 to Charvin discloses a self-contained apparatus for heating food containers having reagents initially separated from one another by at least one watertight partition. The partition is breakable by a rod mounted with radial cutting blades, which blades may be caused to breach the partition by rotation of the rod by an attached rotary control knob protruding from an outside surface of the apparatus. The device in Charvin has cutting blades and is not a low-cost disposable consumer item.
To design a device which is both simple and easy to activate and achieves a reaction going to completion upon full activation, yet simultaneously is comparatively secure against the danger of unintended full activation leading to high temperatures or heat dissipation is not easy. In fact, it appears internally contradictory since a device which readily achieves complete reaction and is not cumbersome to use or manufacture would apparently be one which is only tenuously protected from unintended activation.
Another desirable feature of a portable device for warming beverages, which feature is not well represented in the prior art, is an attention to an optimal temperature and heating rate for various varieties of beverages. For example, the ideal temperature for coffee may be different from that for tea, chocolate milk, soup or baby formula. Furthermore, the ideal rate of heating may be different for each comestible. It should also be noted that a less viscous and purely liquid beverage such as coffee or tea can be heated quicker to ideal drinking temperature since internal convection in the liquid will tend to distribute the thermal energy and prevent local flavor-destroying hot spots or boiling. In contrast, a thicker and partially solid beverage such as soup, must be heated more gradually in order to prevent burning or charring of the contents.
Other prior art devices, moreover, behave in an xe2x80x9call or nothingxe2x80x9d manner, combining reactants in a pre-determined way upon activation, without further user intervention. It is out of the user to control either the final temperature or the rate of heating. Accordingly, there exists a need for a simple portable and self contained food warming device which overcomes the disadvantages of the prior art, provides some control over final temperature and heating rate, is safe, is simple to manufacture and contains few moving parts.
The present invention overcomes the disadvantages of the prior art and offers new advantages. The present invention provides a container assembly having a generally cylindrical container for warming beverages and it includes a flexible closed bottom, a lower compartment and a water compartment. Also included is a generally U-shaped cup that holds the beverage that the user wants to drink warm and has a cover. The cup has an upper portion that fits snugly with an upper perimeter of the container and a lowest part that extends below the surface of the water in the water compartment. Extending from the bottom of the container assembly upward is a lower compartment for a salt compound, preferably calcium chloride, covered by a pierceable partition, typically foil. Perpendicular to the bottom and located in the lower compartment is an annular central divider with a sufficiently sharp upper edge for piercing the partition when pressure is applied to the resilient bottom. The precalculated amount of salt stored in the lower compartment, typically between the annular central divider and the lower compartment outer wall, begins to mix with the water upon the piercing of the partition, and upon shaking of the container assembly it fully mixes with the water and dissolves in it. The exothermic reaction warms the beverage to ideal temperature because of the proportion of water and salt compound and the amount of water set for each kind of beverage.
The following important objects and advantages of the present invention are:
(1) to provide a container assembly for heating beverages;
(2) to provide a container assembly for warming beverages that is self-contained and that is portable;
(3) to provide a container assembly that heats particular beverages to the temperature that is ideal with respect to that beverage;
(4) to provide a container assembly for warming beverages that can be used for a wide selection of beverages;
(5) to provide a container assembly for warming beverages that is simple to use and simple to manufacture;
(6) to provide a container assembly for warming beverages that protects against unintended heating of the beverage or of the container assembly through a two-step heating process;
(7) to provide a container assembly for warming beverages that protects against creating unintended high temperatures in the hands of children;
(8) to provide a container assembly for warming beverages that allows a consumer to drink the beverage at a desirable temperature whenever the consumer wishes to rather than immediately after receiving the warm beverage;
(9) to provide a container assembly for warming beverages that allows a consumer the freedom of movement that comes with not having to limit one""s location to places that offer warming facilities or that offer warm beverages;
(10) to provide a container assembly that includes a generally cylindrical container, a flexible closed bottom, a lower compartment extending from the bottom upward; a water compartment with water, a generally U-shaped cup that holds a particular beverage that needs to be warmed in an interior of the cup, a cover for the cup, and a salt compound;
(11) to provide a container assembly that has a cup having an upper portion that fits snugly with an upper perimeter of the container and wherein the cup is made of a heat transmitting material and is sufficiently rigid to withstand penetration of salt water into the interior of the cup;
(12) to provide a container assembly that has a lower compartment being bounded above by a pierceable partition, and that has an annular central divider in the lower compartment perpendicular to the resilient closed bottom and having a sufficiently sharp upper edge for piercing the partition when a manual pressure is applied upwardly to the resilient bottom;
(13) to provide a container assembly that has a salt compound stored in a lower compartment between a divider and an outer wall of the lower compartment in an amount measured so that the container assembly warms the particular beverage to a specified temperature that is ideal for consumption;
(14) to provide a method of making a container assembly for warming beverages, comprising forming from a mold a generally cylindrical plastic container having an open top, a bottom and a lower compartment extending upward from the bottom with an annular central divider perpendicular to the closed bottom, placing a salt compound in the lower compartment between the divider and a lower compartment outer wall covering the salt and the lower compartment with a partition that is pierceable, pouring water into the water compartment, placing in the container a cup whose upper portion fits snugly with an upper perimeter of the container and putting a cover on the cup and container assembly;
(15) to provide a container assembly for warming beverages using calcium chloride as a salt compound;
(16) to provide a container assembly for warming between approximately two and one half ounces to approximately three and one half ounces of coffee using an exothermic reaction generated from a solution of approximately 7.5 grams of calcium chloride in approximately 9.5 milliliters of water;
(17) to provide a container assembly for warming between approximately two and one half ounces to approximately three and one half ounces of chocolate milk using an exothermic reaction generated from a solution of approximately 9 grams of calcium chloride in approximately 9.2 milliliters of water;
(18) to provide a container assembly for warming between approximately two and one half ounces to approximately three and one half ounces of tea using an exothermic reaction generated from a solution of approximately 7.5 grams of calcium chloride in approximately 9.5 milliliters of water;
(19) to provide a container assembly for warming between approximately two and one half ounces to approximately three and one half ounces of soup using an exothermic reaction generated from a solution of approximately 9.0 grams of calcium chloride in approximately 9.2 milliliters of water;
(20) to provide a container assembly for warming beverages without the need for an external source of heat; and
(21) to provide a container assembly for warming beverages wherein the user has some control over the rate of the heating of the beverage.
Still other objects, features and advantages of the invention, will be apparent from the following description of the preferred embodiments and the accompanying drawings.